144 Mr. Rainey on the formation of [Mar. 30, 



the body of a link may be as simple and easy to remember as possible, and 

 bearing in mind that from circumstances connected with its manufacture 

 the iron in the head of a link is perhaps never quite so well able to bear 

 strain as that in the body, I think it desirable to have the size of the hole 

 a' little in excess, and accordingly for a 10" link I would make the pin 6|" 

 in diameter instead of 6|", that dimension being exactly two-thirds of the 

 width of the body, which proportion may be taken to apply to every case. 

 As the strain upon the iron in the heads of a link is less direct than in 

 its body, I think it right to have the sum of the widths of the iron on the 

 two r sides of the hole 10 per cent, greater than that of the body itself (see 



fig. 5). 



As the pins, if solid, would be of a much larger section than is necessary 

 to resist the effect of shearing, there would accrue some convenience, and a 

 considerable saving in weight would be effected, by having them made 

 hollow and of steel. 



In conclusion, I would remark that my object in writing this paper has 

 been, first, to call attention to the fact that a link is far more likely to be 

 torn by the pin being too small, than a pin to be sheared by a link ; 

 and secondly, to try to establish a simple rule by which their proper com- 

 parative sizes may always be arrived at ; and I have been induced to inves- 

 tigate this very important subject from having generally found in existing 

 suspension-bridge chains a wide departure from what is right in this 

 respect, in having the pins far too small. 



III. " On the Influence of Quantity of Matter over Chemical Affi- 

 nity, as shown in the formation of certain Double Chlorides and 

 Oxalates." By GEORGE RAINEY, M.R.C.S., Lecturer on Micro- 

 scopical Anatomy, and Demonstrator of Surgical Anatomy at 

 St. Thomas's Hospital. Communicated by Dr. GLADSTONE. 

 Received March 2, 1865. 



The simple fact that quantity of matter has the effect of influencing 

 chemical affinity is so well known and so generally admitted, that any 

 special remark upon it would be superfluous; I shall therefore in this 

 communication chiefly confine my observations to the compounds above 

 named, by which this effect will be shown to be strikingly exemplified, 

 offering such explanations and remarks thereon as the nature of the facts 

 may seem to demand. 



The results of nearly all the experiments mentioned in this paper were 

 first arrived at by operating upon very minute quantities of material, and 

 by observing under the microscope the changes that take place ; but after- 

 wards the same products were obtained on the large scale by appropriate 

 processes, and in quantities sufficiently large to admit of being analyzed 

 quantitatively, and of having their formulse accurately determined. I shall 

 therefore commence by giving an account of the processes by which the 



